Carbon Terms

Sometimes you may be familiar with these terms: "Carbon Footprint" and "Carbon Neutral". For those who don't know:

Carbon footprint:
A measure of the amount of CO₂ produced by the activities of an entity [person/organization/state/etc...]

Carbon neutral:

Absorbing the same amount of CO₂ as it produces.

e.g. You produce 1 Kg of CO₂ by your activities and you absorb [trees?] same amount or buy carbon credits to make up the difference.